In a conventional developing device, a layer-thickness regulating blade is fixed by a screw to a blade fixing section in a casing. In a holder for supporting the layer-thickness regulating blade, a surface for fixing the screw is the same as a surface for supporting the blade.
Recently, in order to downsize an image forming device, components of the image forming device such as a developing device and a layer thickness regulating blade are required to be downsized. However, such a conventional configuration of the layer thickness regulating blade increases the size of the developing device.